[Treatment of obstructive sleep apnea syndrome]

Obstructive sleep apnea syndrome (OSAS) is a chronic disorder in which the subject experiences an abnormally large number of episodes of more or less complete and prolonged ventilatory arrest due to pharyngeal obstruction leading to fragmented sleep pattern and reduced arterial oxygen saturation. OSAS produces invalidating daytime symptoms and appears to be associated with cardiovascular complications and overmortality. Diagnosis is based on an exploration of the sleeping pattern with recording of ventilation function, arterial oxygen saturation, heart rate, and electrophysiological characteristics (polysomnography). Prevalence of a high apnea index (more than 5 per hour of sleep) associated with day-time somnolence may be as high as 3% of the population in the 30 to 60 year age range. Current treatment is mainly based on nasal continuous positive airway pressure given via the nasal route during sleep and pharyngeal surgery (uvulopalatopharyngoplasty). Surgery is reserved for subgroups of patients with anatomic abnormalities and free of contraindications for anesthesia. Continuous positive pressure is always effective in case of symptomatic apnea and has a favorable effect on several associated complications. It can be proposed for any patient with OSAS but its use is limited due to incomplete compliance (approximately 70%). It appears that patients with particularly severe disease benefit most. Thus the ANDEM experts recommend treatment for all symptomatic patients with 30 or more episodes of apnea or hypopnea per hour of sleep during night-time exploration. Below this threshold, electrophysiological recordings are required to eliminate another cause of fragmented sleep which could explain the symptomatology despite a moderately elevated apnea index. Once the treatment has been started, regular surveillance is recommended. In addition, general health and nutritional counselling (weight reduction, smoking cessation, interruption of alcohol consumption and use of sedatives) should be proposed but usually have minimal and transitory effect.